1. Technical Field
The invention relates to imaging lenses and, particularly, relates to an imaging lens having a high resolution and a short overall length.
2. Description of Related Art
In order to obtain high image quality, small-sized camera modules for use in thin devices, such as mobile phones, personal digital assistant (PDA), or webcams for personal computers, must have imaging lenses with high resolution but short overall length (the distance between the object-side surface of the imaging lens and the image plane of the camera module). Factors affecting both the resolution and the overall length of the imaging lens, such as, the number and position of lenses employed, the power distribution of the employed lenses, and the shape of each employed lens, complicate any attempt at increasing resolution and shortening overall length of imaging lenses. For example, reducing the number of lenses can shorten the overall length of the imaging lens, but resolution will suffer, conversely, increasing the number of lenses can increase resolution, but increases overall length of the imaging lens.
Therefore, it is desirable to provide an imaging lens which can overcome the abovementioned problems.